I would like to be able to customize these pages but I can't see anywhere the source code. As far as
As far as I could see, the system uses
@page "/authentication/{action}" @using Microsoft.AspNetCore.Components.WebAssembly.Authentication @using Volo.Abp.AspNetCore.Components.Web.Security
https://abp.io/community/articles/how-to-customize-the-login-page-of-an-abp-blazor-application-by4o9yms article to customize auth pages similarly you can change for settings as well.
if you only need to change the application logic then just extend their service and override via dependency injection using [Dependency(ReplaceServices = true)]
visit this link to get full details - https://abp.io/docs/latest/framework/fundamentals/dependency-injection?_redirected=B8ABF606AA1BDF5C629883DF1061649A